Yes. I’ve used mash hopping for thiols, for bitterness, and for complexing metal ions to improve stalling. All with hoppy beer. I’m pretty sure all of this is somewhere on this site if you search and some of it carries links to the appropriate source/research.
From my own limited experience…
I haven’t found any improvement from my thiol experiments. In fact, on occasion the hoppiness in the finished beer tastes more like an alcohol free IPA which to me is a bit artificial/perfumed - not what I wanted and not to my taste.
Bittering is much the same as boil additions but you need to adjust utilisation because of the lower temperatures, much like a hopstand/whirlpool. Bear in mind if you mash hop with pellets they will disintegrate and end up in the boil. Leaf hops are removed with the grain.
Complexing metal ions may be more successful but because I haven’t brewed dozens of batches it could be argued I might have just done a better job of keeping oxygen out of my beer through the brewing process. I do have a bit more confidence in this one though because I’m pretty consistent when it comes to my processes.
As a side note on anti-oxidants I once brewed a beer with lemongrass, geranium leaves, and rose petals because these all contain far higher levels of the oils we cherish in hops and that beer was still clean and hoppy after more than six months. It even got placed (2nd I think) in the American IPAs competition. I unfortunately never got round to brewing a split batch with the three to see if one of these on it’s own could achieve the same results.
